1 files changed, 90 insertions, 0 deletions

diff --git a/src/keeper.hpp b/src/keeper.hpp
new file mode 100644
index 0000000..2354c2e
--- /dev/null
+++ b/src/keeper.hpp
@@ -0,0 +1,90 @@
+#pragma once
+
+#include "uniquekey.hpp"
+
+// forwards
+class Linda;
+enum class LookupMode;
+class Universe;
+
+DECLARE_UNIQUE_TYPE(KeeperState,lua_State*);
+DECLARE_UNIQUE_TYPE(LindaLimit, int);
+DECLARE_UNIQUE_TYPE(KeeperIndex, int);
+
+// #################################################################################################
+
+struct Keeper
+{
+    std::mutex mutex;
+    KeeperState K{ static_cast<lua_State*>(nullptr) };
+
+    [[nodiscard]] static void* operator new[](size_t size_, Universe* U_) noexcept;
+    // can't actually delete the operator because the compiler generates stack unwinding code that could call it in case of exception
+    static void operator delete[](void* p_, Universe* U_);
+
+
+    ~Keeper() = default;
+    Keeper() = default;
+    // non-copyable, non-movable
+    Keeper(Keeper const&) = delete;
+    Keeper(Keeper const&&) = delete;
+    Keeper& operator=(Keeper const&) = delete;
+    Keeper& operator=(Keeper const&&) = delete;
+
+    [[nodiscard]] static int PushLindaStorage(Linda& linda_, DestState L_);
+};
+
+// #################################################################################################
+
+struct Keepers
+{
+    private:
+    struct DeleteKV
+    {
+        Universe* U{};
+        size_t count{};
+        void operator()(Keeper* k_) const;
+    };
+    // can't use std::vector<Keeper> because Keeper contains a mutex, so we need a raw memory buffer
+    struct KV
+    {
+        std::unique_ptr<Keeper[], DeleteKV> keepers;
+        size_t nbKeepers{};
+    };
+    std::variant<std::monostate, Keeper, KV> keeper_array;
+    std::atomic_flag isClosing;
+
+    public:
+    int gc_threshold{ 0 };
+
+    public:
+    // can only be instanced as a data member
+    static void* operator new(size_t size_) = delete;
+
+    Keepers() = default;
+    void close();
+    [[nodiscard]] Keeper* getKeeper(KeeperIndex idx_);
+    [[nodiscard]] int getNbKeepers() const;
+    void initialize(Universe& U_, lua_State* L_, size_t nbKeepers_, int gc_threshold_);
+};
+
+// #################################################################################################
+
+// xxh64 of string "kNilSentinel" generated at https://www.pelock.com/products/hash-calculator
+static constexpr UniqueKey kNilSentinel{ 0xC457D4EDDB05B5E4ull, "lanes.null" };
+
+using keeper_api_t = lua_CFunction;
+#define KEEPER_API(_op) keepercall_##_op
+
+// lua_Cfunctions to run inside a keeper state
+[[nodiscard]] int keepercall_count(lua_State* L_);
+[[nodiscard]] int keepercall_destruct(lua_State* L_);
+[[nodiscard]] int keepercall_get(lua_State* L_);
+[[nodiscard]] int keepercall_limit(lua_State* L_);
+[[nodiscard]] int keepercall_receive(lua_State* L_);
+[[nodiscard]] int keepercall_receive_batched(lua_State* L_);
+[[nodiscard]] int keepercall_send(lua_State* L_);
+[[nodiscard]] int keepercall_set(lua_State* L_);
+
+DECLARE_UNIQUE_TYPE(KeeperCallResult, std::optional<int>);
+[[nodiscard]] KeeperCallResult keeper_call(KeeperState K_, keeper_api_t func_, lua_State* L_, Linda* linda_, StackIndex starting_index_);